Prediction of manyelectron wavefunctions using atomic potentials: extended basis sets and molecular dissociation
Abstract
A oneelectron Schroedinger equation based on special oneelectron potentials for atoms is shown to exist that produces orbitals for an arbitrary molecule that are sufficiently accurate to be used without modification to construct single and multideterminant wavefunctions. The exact Hamiltonian is used to calculate the energy variationally and to generate configuration interaction expansions. Earlier work on equilibrium geometries is extended to larger basis sets and molecular dissociation. For a test set of molecules representing different bonding environments, a single set of invariant atomic potentials gives wavefunctions with energies that deviate from configuration interaction energies based on SCF orbitals by less than 0.04 eV per bond or valence electron pair. On a single diagonalization of the Fock matrix, the corresponding errors are reduced 0.01 eV. Atomization energies are also in good agreement with CI values based on canonical SCF orbitals. Configuration interaction applications to single bond dissociations of water and glycine, and multiple bond dissociations of ethylene and oxygen produce dissociation energy curves in close agreement with CI calculations based on canonical SCF orbitals for the entire range of internuclear distances.
 Publication:

Physical Chemistry Chemical Physics (Incorporating Faraday Transactions)
 Pub Date:
 October 2019
 DOI:
 10.1039/C9CP02450F
 arXiv:
 arXiv:1909.05935
 Bibcode:
 2019PCCP...2121541W
 Keywords:

 Physics  Chemical Physics
 EPrint:
 Phys. Chem. Chem. Phys., 2019, 21, 21541